Easiest way? pay someone else to do it haha. but its pretty straight forward if you read the DYI/Guides. Not sure how much simpler you can make it xD

I believe that video is very similar to what you have to do when installing the bms box just follow the guide for BMS on which wires to remove, put in, etc. Should help more or at least give you a visual guide of what should be done.

I have a 09 328i N51 and I have had the BMS power box on my car for about 4 months. I'm putting true dual exhaust on it tomorrow and I will do a post exhaust dyno as well but here is what it did with it on and off. Setting 3 is what I leave it on.

I also used heat shrink on my wire connections not stupid tape like they show......